Stop plan

I am in a trainingplan but having a knee surgery.
Can I pause the plan or will I have to leave at start over?

Depends how long you will be out of action, how long the plan is and how far you are into it and how long to an event if you have one that you are preparing for. If it is a 12 week one and you are out of action for less than say two weeks I would just move the whole lot forward two weeks. A 4 week plan with two weeks off then I would just start again. For me, I had a weeks holiday and just moved everything forward a week but any longer I would have just started again as I had the time.

Yep. The way I look at it is that a plan is designed to optimally achieve the stated objective base on your 4DP profile, your inputs when choosing a plan, and does this with the scheduling of the various types/intensities/durations of the workouts scaled over time. A significant interruption puts a kink in that. It depends on the type, duration, and where you are in the plan, but I figure if there is significantly more than a week off, I’d likely just start a new plan at that time, perhaps one based on the 4 week building block plans depending on the time available. I always start a plan with a 7 day test prep plan that includes a HM on day three and FF on day 7. IMO, it not only produces reliable test results, it’s also a solid week of workouts.